The present invention relates to a master negative film forming device, a master negative film forming method and a master negative film, and can be suitably applied to the case of recording digital audio data onto movie film for example.
Heretofore, as shown in FIG. 8, on movie film 1, multiple frame pictures forming a series of moving pictures are recorded sequentially frame by frame, and an analog audio signal track 5 on which analog audio signals are recorded is formed along the internal part of one of two series of perforations 3 provided on both sides in the longitudinal direction of the film. In addition, a digital audio data track 4 on which digital audio data is recorded is formed along the external part of both perforations 3.
As shown in FIG. 9, the digital audio data track 4 of this movie film 1 is composed of multiple blocks representing one bit data per one block, and comprised of line synchronization pattern 8, tracking pattern 9, main signal pattern 10 and azimuth detection pattern 11.
The line synchronization pattern 8 is comprised of multiple blocks for 2 rows in the longitudinal direction of the film and shows whether signal elements exist or not in the main signal pattern 10 in a column direction perpendicularly intersecting to the longitudinal direction of the film. In the case of FIG. 9, two blocks in each column of the line synchronization pattern 8 are unexposed and this shows that signal elements of the main signal pattern 10 exist in each column direction.
The tracking pattern 9 is comprised of multiple blocks for four rows in the longitudinal direction of the film. And this is the checkered pattern showing the exposed part and unexposed part for 2 blocks in each column shifted by a half block with respect to each block of the line synchronization pattern 8.
The main signal pattern 10 is formed of multiple blocks of eight rows in the longitudinal direction of the film on the same level as the line synchronization pattern 8. Digital audio data is recorded on eight blocks in each column, and the azimuth detection pattern 11 for two rows of blocks having the same checkered pattern as the tracking pattern 9 is adapted to appear at the starting point of each frame picture 2.
In such a digital audio data track 4, guard band 12 having the prescribed width is formed in the row and column directions between blocks in the line synchronization pattern 8, the tracking pattern 9 and the main signal pattern 10, which prevents signal elements of a block from the interference (cross-talk) with those of the neighboring blocks in the row and column direction.
In the case of reproducing such movie film 1, while the movie film reproduction device 15 runs the movie film 1 run in the direction shown by an arrow at the prescribed speed, as shown in FIG. 10, it radiates the light source light from the light source 20 to the frame picture 2 of the movie film 1 sequentially frame by frame to project it on a screen 22 as the moving picture via a lens 21.
At the same time, the movie film reproduction device 15 radiates the light source light from the light source 23 to the digital audio data track 4 of the movie film 1 and captures the transmission light of the digital audio data track 4 at the readout timing when the guard band 12 of the tracking pattern 9 in the column direction becomes center in the light receiving area (FIG. 9) of the CCD camera 25.
Then, the movie film reproduction device 15 outputs an output signal of the CCD camera 25 obtained via the tracking pattern 9 to the tracking adjusting circuit 26. The tracking adjusting circuit 26, forming a tracking control signal S1 based on the output signal of the CCD camera 25 and by transmitting this to the CCD camera 25, conducts the tracking adjustment in order that the ratio of upper two blocks of the exposed part and lower two blocks of the unexposed part become equal centering around the guard band 12 of the tracking pattern 9 in the column direction.
On the other hand, the movie film reproduction device 15 outputs the digital audio data of the main signal pattern 10 captured by the CCD camera 25 to a digital conversion circuit 27 while conducting the tracking control within light receiving area by the CCD camera 25. And the digital conversion circuit 27 converts this digital audio data into an analog audio signal and after amplifying this to the prescribed level through an audio signal output circuit 28, outputs sound from a speaker 29.
The movie film 1 is a positive film to be formed by performing optical contact printing on master negative film and blank film which has no picture recorded thereon. Its forming process is that firstly digital audio data is recorded on master negative film at a prescribed gray value (recording density), and after, by performing the contact printing on the master negative film and blank film are contact-printed, the digital audio data is transferred to a positive film, which is blank film, at a proper gray value. Here, the gray value (density) is a value representing a degree of darkness of film. And the proper density is a value of the time when digital audio data to be optically transferred to positive film is recorded at such density as to be correctly read by the reproduction device, and is previously set taking the properties of negative and positive film, the size of digital audio data, the functions of the reproduction device and other conditions into consideration.
In practice, as shown in FIG. 11, the movie film forming device 40 runs a blank film on which nothing is recorded, in the direction shown by an arrow A and moreover, runs a negative film 31 on which digital audio data is recorded, in the same direction as the arrow A at the same speed, and radiates the light source light with the predetermined radiation intensity to the blank film 30 from the light source 32 via the digital audio data track in order to record the digital audio data onto the blank film 30 at the aforementioned proper gray value.
At this point, the movie film forming device 40 records the digital audio data on the blank film 30 and at the same time, runs the negative film 33 on which the still picture is recorded, in the same direction as the arrow A, and by radiating the light source light from the light source 34 to the blank film 30 via the frame of the negative film 33, records multiple still pictures onto the blank film 30 frame by frame.
In this way, the movie film forming device 40 records still pictures and digital audio data on the blank film 30 to form a positive film 35, and displays this on the screen as the movie film 1 via the movie film reproduction device 15 (FIG. 10).
However, in the movie film forming device 40 having the aforementioned configuration, there are cases where printing is performed at a higher gray value (darker) than the proper value when the positive film 35 is formed. And this makes the contrast between exposed areas and unexposed areas clear in the digital audio data track 4 of the positive film 35 and increases the dynamic range.
In practice, as shown in FIG. 12, in the case where the positive film 35 is formed at the higher gray value than the proper value based on the master negative film 31 on which guard band 41 having the prescribed width are formed in the tracking pattern, the blur spread out from the exposed part including the guard band 12 of the positive film 35 to the unexposed part and thus the unexposed area is eroded by the blur.
In such cases, as shown in FIG. 13, a signal level in the tracking pattern 9 of the positive film 35 captured by the CCD camera 25 of the movie film reproduction device 15 (FIG. 10) drops to the level D, almost close to 0 because the area of unexposed part (easy to transmit the light) is decreased by the erosion of blurs.
Accordingly, the most of the unexposed part of the positive film 35 printed at extremely higher gray value than the proper value is all covered with the blur. In such cases, the movie film reproduction device 15 cannot obtain any signal element from the tracking pattern 9 even when the timing of the readout from the light receiving area (FIG. 9) of the CCD camera 25 is shifted a little in the longitudinal direction of the film. And this caused a problem that it was difficult to conduct the tracking adjustment (the readout timing adjustment so that the CCD camera 25 can read the center of a column of the main signal pattern 10 within the light receiving area).
On the other hand, regarding the positive film 35 when the printing is conducted at the lower gray value than the proper value based on the negative film 31, since the exposed part is not fully exposed to light, the area of the unexposed part (easy to transmit the light) is increased as a whole, and as a result, the signal level of the output signal of the CCD camera 25 goes up to the level E.
However, since the tracking pattern 9 and the main signal pattern 10 are printed at the same gray value when the positive film 35 is formed, the signal level of the output signal in the main signal pattern 10 of the CCD camera 25 and the signal level of the output signal in the tracking pattern 9 are almost changed together according to the gray value.
In the movie film reproduction device 15, in the case of binary-judging xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d of the digital audio data read out from the main signal pattern 10 of the positive film 35, binary data is to be judged by using the signal level obtained from the tracking pattern 9 when printing is conducted at the proper gray value as the threshold level A shown in FIG. 14 in the digital analog conversion circuit 27. In this connection, the threshold level A in the tracking pattern 9 becomes slightly lower than the ideal threshold level (FIG. 13) at the time when the main signal pattern xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d is judged taking the existence of exposed guard band 12 into consideration.
Accordingly, in the movie film reproduction device 15, when the signal level from the tracking pattern 9 of the positive film 35 drops to D level due to large amount of erosion by the blur, it is necessary to decrease the threshold level A when binary judging xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d of the digital audio data recorded in the main signal pattern 10. On the other hand, if the gray value is extremely lower than the proper value and the signal level is increased to E level, it is necessary to increase the threshold level A when binary judging xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d of the digital audio data.
Thus, in the movie film reproduction device 15, although it is necessary to change the threshold level A at the appropriate time when binary judging xe2x80x9c1xe2x80x9d and xe2x80x9c0xe2x80x9d of the digital audio data according to the gray value, it is very difficult to change the threshold level A corresponding to the gray value when making the positive film 35 because it requires complicated processing.
The present invention has been done considering the above points and is proposing a master negative film forming device, a master negative forming method and a master negative film capable of forming reproduction film having stable reproduction characteristics constantly with a simple construction and method.
To obviate such problems according to the present invention, in the case of forming the master negative film when the master negative film on which data is recorded is exposed at the predetermined gray value to transfer the data to the reproduction film, multiple exposed areas and unexposed areas having prescribed shapes are arranged alternately. And in the case of forming the readout pattern having guard bands between an exposed area and an unexposed area, on the master negative film as a pattern for controlling the readout timing of the data transferred to the reproduction film, the width of guard band is controlled based on the gray value, thereby the signal level to be obtained from unexposed areas of the readout pattern transferred to the reproduction film is to keep the fixed relative value with respect to the signal level to be obtained from the data part transferred to the reproduction film.
In the case of forming the readout pattern on the master negative film, the width of the guard band is controlled based on the gray value in order that the signal level to be obtained from the unexposed areas of the readout pattern transferred onto the reproduction film keeps the fixed relative value with respect to the signal level to be obtained from the data part transferred onto the reproduction film. Thereby, the area of unexposed area can be controlled within the area even the quantity of the blur of the exposed area changes according to the gray value of the formed reproduction film, and the data can be read out correctly based on the fixed signal level obtained from the unexposed area.
In the master negative film for transferring prerecorded data onto the reproduction film at the predetermined gray value, multiple exposed areas and unexposed areas having the prescribed shapes are arranged alternately, and at the time when the readout pattern having guard bands between each exposed area and each unexposed area is formed as a pattern for controlling the readout timing of the data, since the width of the guard band is controlled according to the gray value, the signal level to be obtained from unexposed area of the readout pattern transferred onto the reproduction film is to keep the fixed relative value with respect to the signal level to be obtained from the data part transferred onto the reproduction film.
In the case where the readout pattern is formed on the master negative film to be used when the prerecorded data is transferred onto the reproduction film at the prescribed gray value, the width of guard band is controlled according to the gray value so that the signal level to be obtained from the unexposed area of the readout pattern transferred onto the reproduction film keeps the fixed relative value with respect to the signal level to be obtained from the data part transferred onto the reproduction film. Accordingly, even if the amount of the blur of the exposed area changes according to the gray value of the reproduction film, the area of unexposed part is controlled within the fixed area and the data can be correctly read out based on the fixed signal level obtained from the unexposed area.